Just about every baby is a rootin’ tootin’ machine. Why? Gut bacteria that break down food naturally create gas, no matter your age. Since babies eat around the clock, they’re making bubbles 24/7. Infants can also swallow a lot of air when they cry or eat, especially if they’re bottle-fed. Burping your baby during and after feedings, bicycling his legs, and plenty of tummy time help gas make its way out.

Spitting up is very common no matter if you breastfeed or give your baby formula. But bottle-fed babies may swallow more air while they eat, which makes spit-up more likely. If your baby projectile vomits, seems uncomfortable, or doesn’t want to eat, though, she may have gastroesophageal reflux disease (GERD). It seems to affect breastfed babies less often than formula-fed babies.

Lying down or bending at the waist can trigger spit-up, so try to keep him in an upright position during feedings and for 20 to 30 minutes afterward. That means avoiding tummy time and diaper changes when his stomach is full -- barring any poop explosions. If you burp him during and after each feeding, you can also reduce the risk of an air bubble bringing up some food with it.

Don’t worry: it’s normal to see a sticky black tar in there in her first days of life. The good news: this waste, called meconium, is odorless. As she starts to eat, you’ll notice that her poop color changes, from black to dark green to yellow. If you breastfeed her, it may be lighter in color, runny, and seedy looking, while formula-fed babies may make thicker, yellowish-brown stools. When she starts to eat solids, the poop will get firmer (and stinkier).

Some kids poop after every feeding. Others, particularly those that are breastfed, can go several days, even a week, without a bowel movement. But if your little one suddenly gets off his usual schedule, bring it up with the doctor. It could mean he has a digestive issue.

Pooping is hard work for infants, and straining could simply mean that yours hasn’t learned to properly relax his muscles yet. As long as his stool is still soft, he’s probably OK. Signs of constipation include hard or very large bowel movements, blood in the stool, or going longer than usual between poops.

After an all-liquid diet, solids can sometimes block things up before the digestive tract adjusts. Spoon-feeding her more fiber-rich fruits and veggies can bring relief, or your pediatrician may suggest giving small amounts of fruit juice, like prune, pear, or apple, or dark corn syrup to help soften stools. If your baby is eating lots of rice cereal, which can be constipating, try switching to oatmeal or barley cereal.

Infants should have at least six wet diapers a day, and going more than 3 hours without peeing can be an early sign of dehydration. Other signs to watch for: Your child cries but doesn’t make tears, the soft spot on her head looks deeper or sunken, or her mouth or tongue seems dry. Your pediatrician may tell you to just keep up her regular feedings, or recommend electrolyte solutions or IV fluids.

Experts aren’t sure what causes these long bouts of crying. But it happens more than twice as often in babies whose mothers have migraines. Other studies have pointed to gut inflammation and too little gut bacteria or moms who smoke as possible causes. There might also be a milk allergy at play. Whatever the cause, colic typically goes away on its own by the time a baby is 3 or 4 months old.

A baby’s stools are often quite soft, but it’s important to watch for signs of diarrhea. It can happen because of a stomach bug or food poisoning, which commonly spreads at day care centers. Diarrhea that happens over and over might mean an allergy to cow’s milk or another food. If your baby’s poop suddenly gets watered-down, especially if it has blood or is very smelly, or if he seems fussy or sick, call your pediatrician.